Is this dish ok?

[Channel Hopper]

I dont suppose you have any examples? I cannot find any info on checking its dead center

_http://www.mi-technologies.com/literature/mit12.pdf

Use the section for 'near field' alignment.

 

[garyg]

Thanks mate,

I realised my lnb holder was not straight and the lnb points to far down, almost on the bottom sections (below the hole).

Hopefully my proper bracket comes tomorrow

 

[Robbo]

I remember trying to get that feedhorn pointing to the middle, one of the methods I used was to take the lnb off and look down the hole.

 

[garyg]

what dish did you use it on mate? And did you get it working ok in the end?

 

[Robbo]

It was a 1.8 PF, and yes I did, for Nilesat H. I then received a matched feedhorn for the dish, performance was the same, but less improvised. My mount for the Invacom feed consisted of a triagular plate with a hole in earch corner and bent a bit, to which I fixed a Triax 40mm to 23mm reducer (the one I sent you with the feedhorn LOL), fixed to the plate with self tappers, into the plastic. It did work though, honest, very well. The main factor was that I had a reasonable amount of in/out ajustment.

 

[garyg]

lol!

Well hopefully my mount comes tomorrow for the lnb!

Yeh I got your plastic reducer on my desk lol, looks like it should work

I am begging my dish gets signal tomorrow or else I am screwed!!

 

[Huevos]

one of the methods I used was to take the lnb off and look down the hole.

That only proves the LNB is pointing at the centre of the dish, but it doesn't prove the LNB is centred. You'd need a mirror in the centre of the dish to prove that.

 

[Robbo]

Yes, but the LNb arms themselves held the LNb at the centre of the dish, I also attached a 'stick' that I found in my garden to the feedhorn, and 'eyed' that up too. On th eparticular dish I had, there really wasn't any way the arms could put the LNB away from the centre.

 

[garyg]

all interesting comments

Cant wait for the morning!!! need my bracket

 

[Robbo]

lol!
I am begging my dish gets signal tomorrow or else I am screwed!!

It has to work better than than the 1.8m Gary, it really doesn't have a choice, given the lengtho of this thread and the number of views it has had.

 

[garyg]

It has to work better than than the 1.8m Gary, it really doesn't have a choice.

im just worried i wont mount the lnb right or something...

I am just going to get a flat sheet of metal 3 or 4mm thick, put a hole in the middle for the lnb and bracket, and then drill the holes for the 4 arms, and the 3 bolt holes for the bracket.

So it will all sit flush just 3mm difference due to the metal for the adapter... so fingers crossed it sits ok!

Will it sid straight when connected to all the arms?

 

[Robbo]

Lets hope so, or the mallet may be in order (only joking!)

 

[Huevos]

Yes, but the LNb arms themselves held the LNb at the centre of the dish

Well in theory yes but in practice no. On the Famaval 2.4m, for example, those supports are pretty long and have a dogleg in them so it is possible to get the LNB quite a bit off centre, and we are only talking a 2.5cm wavelength, so even just a few millimeters out eats into the performance. Much less problem with an offset dish because the focal distance is so much longer.

 

[garyg]

Ok,

Think rolf will have to help me find the lnb center then once i have mounted the lnb

 

[Robbo]

Ahh yes I see, with a dogleg. ON mine it was straight poles fixed directly to the holder, unless a pole was bent it was not possible, would have to revisit Garys piccies to see what his arms are like.

 

[garyg]

have a look mate, there not straight poles tho

 

[Huevos]

Gary, I really wouldn't worry too much. It's going to work fine. Right now you are already able to receive stuff from Badr6 and the dish hasn't been aligned with a meter nor has the LNB depth been adjusted.

 

[garyg]

i wouldnt say badr6 mate but i can off badr4. badr6 is around 30% so no lock.

I wont worry until the meter fails. Although I will worry

 

[Robbo]

I just hope that holder comes on Monday, I can't stand the suspense for much longer!

 

[garyg]

i hope it does to... it was recorded delivery sent friday.

Im going to goto sleep soon I think! Need to wake up for the postman haha.